HD650 Dynamat Mods - Proof That It's Not BS

Discussion in 'Modifications and Tweaks' started by purr1n, May 16, 2016.

  1. purr1n

    purr1n Finding his inner redneck

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    HD650 Dynamat Mods - Proof That It's Not BS!

    So far, those of us who have done the standard measurements have found no conclusive proof via measurements that the Dynamat Extreme mods even do anything, and that this mod could be placebo. @CEE TEE gave me his HD650 and asked to perform the final touches of the HD650 M mods. He mentioned it didn't sound right, that his didn't sound like mine with the full mods. I wasn't too sure myself about the Dynamat Extreme mods, so I took this opportunity to take another look. This time with some different kinds of measurements.

    Note that "stock" does not denote stock, but with the quarter mod and foam removal mod already implemented. "Modded" means the addition of the Dynamat Extreme to the quarter/foam modded headphone.

    20160516_222507 (Medium).jpg

    Full Spectrum, 1kHz Tone. Top = Stock, Bottom = Modded
    DMX 1kHz.png
    Note lower noise floor in the bass? Could this be attributed to better environmental conditions when the modded HD650 measurements were taken? Let's explore more.

    Full Spectrum, 75Hz Tone. Top = Stock, Bottom = Modded
    DMX 75Hz.png
    Note lower noise floor in the sub and low bass region. Also note lower 4th and 5th order distortion and slightly lower 3rd order.

    Full Spectrum, 50Hz Tone. Top = Stock, Bottom = Modded
    DMX 50Hz.png
    Again, note lower noise floor in the sub and low bass region. Just cleaner all around the 50Hz tone. Also note lower distortion from 3rd order on.
     
    Last edited: May 17, 2016
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  2. purr1n

    purr1n Finding his inner redneck

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    Let's look at CSDs. I took three separate measurements to confirm. They graphs looked pretty much the same.

    hd650 R stock.jpg
    mod 3.jpg
     
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  3. Armaegis

    Armaegis Friend

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    I'd be curious to see the effects of:
    - heavier mass loading
    - increased clamp (which would in theory increase mechanical coupling*)

    * I have a suspicion that different pads change the coupling properties as well, but the effects of that would be dwarfed by the different acoustic properties
     
  4. Artasia

    Artasia Friend

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    Interesting that the Dynamat is all up on that magnet hole. Hands and some others claimed the dynamat should be held off by at least 3mm from the center holio, I thought, unless its been discovered that dynamat should be all up in that shit.
     
  5. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Did you hear any differences between yours and @CEE TEE's HD650? And figure out why?

    I'm now inspired to finally remove the spider so I can put more DM on the magnet, and also do the non-reversible quarter mod.
     
  6. TraverS

    TraverS Rando

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    Do you mean 50Hz and 75Hz for the last two signal.
     
  7. purr1n

    purr1n Finding his inner redneck

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    No differences after mod. Before, yes. The mod makes everything sound tighter and results in more plankton. I am sure of my initial subjective impressions now. As CT mentioned, his HD650 just wasn't quite tright (like mine) without this last procedure.

    Yes. Fixed. Thanks.
     
  8. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Not to <beat dead horse>, but the two phones sounded different with all the mods, just Dynamat done differently? Or CT's didn't have the Dynamat on yet? I guess the latter makes more sense, allowing you to do the comparison.
     
  9. purr1n

    purr1n Finding his inner redneck

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    With all mods, they sounded the same. I did more work on CT's HD650 than mine, so his might be slightly better. But there is diminishing returns with Dynamat.
     
  10. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    It's possible it could be beneficial. I was trying to minimize changing the acoustic properties of the port. If you put the Dynamat right up against the port, in theory, you'd be extending the length. Keeping it 2-3mm away should hopefully minimize changes like that, though, like I said, it could be beneficial, or it could make basically no difference.

    I noticed Dynamat improved my impulse response slightly, though I can't remember if I shared that or not. IR is hard to replicate exactly on a day-to-day basis with my setup.
     
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  11. Riotvan

    Riotvan Got lost for three weeks at Delft City Hall

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    Mine is about 2mm from the hole and it is tapered in towards the center.

    Still thinking about covering the holes up with dynamat but it seems opinions are divided on that.
     
  12. Jun

    Jun Friend

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    At first I compared Dynamat on and off the drivers and I liked it with nothing behind the drivers. Then later I got bored and gave Dynamat on the driver another shot for a week. Then I took it off and thought it sounds much better without Dynamat on the drivers. Dynamat on the driver does tighten things up, it feels like reversing the spider cage and foam removal. Now these measurements are making me want to put the Dynamat back on the driver.
     
  13. Mr.Sneis

    Mr.Sneis Friend

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    Was just reminiscing about how I really hated the HD650 with foam removal/quarter mods, the dynamat must be making up for it somewhere?
     
  14. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    What didn't you like about the mods exactly? Dynamat may or may not change your opinion. It's a more subtle change.
     
  15. Mr.Sneis

    Mr.Sneis Friend

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    This is all from old old memory now but the worst for me was added fatigue where there wasn't any before.
     
  16. Riotvan

    Riotvan Got lost for three weeks at Delft City Hall

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    I heard the same, dynamat fixed that for me. Less distortion and more resolution is what my ears tell me. Don't have a measurement rig so take that with a grain of salt.
     
  17. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Probably a slight boost in treble due to hole cutout mixed with no buffer between driver and back plastic spider (reflections). I had to remove the plastic spider to fix this issue. Also am running the K240 foam now, which helps further. Dynamat didn't fix this so much.
     
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  18. Serious

    Serious Inquisitive Frequency Response Plot

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    @Marvey
    Can we get long time scale CSDs that go all the way down to 20Hz? (like 50ms or so). Could be that there would be some improvements there, or maybe not.
     
  19. purr1n

    purr1n Finding his inner redneck

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    No, because it takes 50ms for a 20Hz cycle to propagate. I'm not sure even the impulse response window is that long.

    EDIT: I ran some quick burst decays. Inconclusive. Too much dictated by environment, e.g. Marine Cobra attack helicopters flying overhead, guy with monster truck a few streets over, neighbor yelling at this son, etc.
     
    Last edited: May 17, 2016
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  20. zerodeefex

    zerodeefex Grumpiest admin

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    @CEE TEE did you ever compare yours to mine?
     

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